Steam boiler system



June 1933. w. M. RYAN ET AL STEAM BOILER SYSTEM 2 Sheets-Sheet 1 FiledMarch 2, 1931 June 2Q, 1933 w. M. RYAN El AL STEAM BOILER SYSTEM FiledMarch 2, 1931 2 Sheets-Sheet 2 Patented June 20, 1933 UNITED STATESPATENT OFFICE WILLIAM H. RYAN AND B. FAVERTY, OI CHICAGO, ILLINOIS,ASSIGNORS TO RYAN CAR COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS STE-AM BOILER SYSTEM Application filed March 2, 1931. SerialNo. 519,491.

ing the firing up period. The deficiencies.

alluded to will be explained more fully in the body of thespecification, but for the pres-' ent it may be said that thesedeficiencies manifest themselves in too frequent burning of the tubes orcirculating coils, and in re- 1 quiring a somewhat greater lengthof timeto bring the system up to full capacit than should be required with themost satis actory functioning of the system.

The principal object of the present invention is to improve steam boilersystems.

Another object is the provision of an improved starting method for steamboiler systems of the character referred to.

Another object is to increase the life of-the circulating coils employedin such systems.

Another object is initially to promote circulation of fluid through thecoils in the normal direction.

Another object is to present to the burner on initial firinga set ofcoils substantially filled with water, whereby the burning out of tubesdue to the overheating at the starting period is revented.

Another ob ect is to operate a boiler system so as to make the systemimmediately available for the building up of pressure therein when theburner is ignited.

Other objects and features of the invention will be apparent from aconsideration of the following detail description talren with theaccompanying drawings, wherein,

Fig. 1 is a schematic lay-out of the system as applied to a particulartype of installation, and

Fig. 2 shows the steam generating system somewhat more in detail.

59 In the system to which the" present invention is applied, a steamgenerator is employed, includin a burner about which are disposed aplura ity of circulating coils comprising in general practice waterpre-heating coils, evaporating coils and steam super-heating coils.Water is fed to the pro-heater coils by a force pump and this water isdelivered from the pre-heater coils to the evaporator coils through aninjector which draws additional water for the evaporating coils from thebottom of a steam and water separatin drum forming part of the system.The e uent from the evaporator coils is discharged tangentially at thetop of the drum, unvaporized water particles falling to the bottom ofthe drum and the steam remaining at the top of the drum, whence it isdelivered by a pipe to the steam super-heating coils. From the steamsuper-heating coils the steam is delivered to the point of use, such asa multi-cylinder steam engine for driving a rail car.

This type of steam generator is operated as a general rule on a closedsystem basis, exhaust steam being discharged into a condenser whichdelivers the condensate through suitable means back into the system. Avery important feature of a system of this character distinguishing itfrom the old type of steam locomotive is the fact that from a coalstart, steam can be generated in a relatively short length of time. Whenthe system is used on a rail car, for example, such car is usually usedon a portion of the transportation system where an ordinary locomotiveis unsatisfactory, due to long lay-overs or other conditions, whichmakes the new type rail car more desirable. It is found in actualpractice that the system is allowed to cool down, necessitating frequentstarting from.

a cold system, as a rule much oftener than is the case with a steamlocomotive.

When the system cools, a-vacuum is created the drum. On starting, thecoils will then contain less than the normal and required amount ofwaterfor proper operation and due to the shortage of water over-heating mayresult with an injury to the coils. The evaporating and steamsuper-heatin coils are closest to the burner and will receive the heatof the burner more quickly and more intensely than the proheater coils.The residual moisture in these coils is quickly driven off, therebymaking the coils substantially bone-dr and permitting them to becomeintensely ot, due to their close exposure to the burner. Suchcirculation as is initially set up in the first stages of starting willrather. tend to cause reversed circulation of the water in the boilersthan normal circulation and so will delay the normal movement of thewater from the pre-heating coils into the evaporating coils. This isshown by the fact that often the injector will not begin to functionuntil the steam pressure has reached as high as 400 lbs. When thecirculation is finally set up so that water is supplied tothe overheatedtubes, these tubes operate almost as a full flash boiler. intendedmanner of operation of these tubes or coils, the system will notfunction with satisfaction until the overheated coils have been broughtsubstantially back to a normal temperature and operative circulationestablished. In the starting of the present type of steam system withoutthe improvements of our invention, we find that the steam pressureincreases in steps, a relatively rapid rise in pressure being followedby a lag period in which the pressure will remain substantially uniformor even may be lowered slightly. According to the general method practiced by-us, we overcome these difficulties by breaking the vacuum inthe system during the cooling period so that the coils on initialstarting will be substantially filled with water, with the exception ofcourse of the steam super-heating coils, which in the design of thesystem are not to contain water. Near the discharge point of thesuperheat- -ing coils we provide bleeder means for venting the highpressure steam line, this venting means being operative until the systemattains a pre-det-ermined pressure, at which time normal operatingconditions have been brought about and the system is substantially readyto supply steam at the normal operating pressure.

Referring now to Fig. 1 of the drawings, we show a steam generator 10,(shown more in detail in Fig. 2), a steam engine 11-, a condenser 12,receiving discharge steam from the engine, a water supply tank 13, and apump 14 for drawing water from the supply tank and delivering it underpressure to the steam generator, the pump being operated -by suitablemeans, for example, an electric motor 16.

Since this is not the Referring now to Fig. 2, the steam generatingsystem includes a main burner 17 adapted to be supplied with fuelvaporized and forced under pressure to the burner with air from a blower18. The fuel delivered into the passageway 19 in an atomized condi: tionis vaporized by contact with a hot plate 21, which is maintained at anelevated temperature by a pilot burner 22 of suitable type. In the formshown a suitable temperature is'initially imparted to the pilot burnerby electrical heating coils 23. A burner of this character is operatedunder conditions and in a manner not of prime importance in connectionwith the present invention. It is suflicient to state that the burneroperates at a very elevated temperature, producing a clear bluenon-radiant type of flame, which is visible under normal operatingconditions not more than an inch away from the burner. It will beunderstood that the character and intensity of this flame is importantin connection with the operation of the burner,.as it will quickly causean overheating of the tubes, if they are not supplied with'suificientwater to keep the temperature thereof below any possible danger point.

Around the burner and within the casing 24 are grouped the coils,including evaporating coils 26, steam super-heating coils 27 and waterpre-heating coils 28. Water is delivered to the coils 28 through a pipe29 and the pre-heater coils deliver water to a pipe 31 communicatingwith an injector 32, which through a pipe 33 drawsaddition'al water fromthe bottom of a drum 34. From the injector water is delivered through apipe 36 to the evaporator coils 26 and the steam mixed withwater'particles with some water is discharged from the evaporating coilsthrough a pipe 37 into the top of the drum 34. The pipe '37 preferablyhas an outlet part within the drum disposed tangentially thereof tofacilitate separation of water and steam, the water falling to thebottom of the drum and the steam remaining in the top portion thereof. Apipe 38 communicating with the top of the drum withdraws steam therefromfor delivery to the super-heating coils 27 and the super-heated steam isdelivered from the super-heating coils through a pipe 39, which,'through suitable control means, is adapted to be delivered to the placeor places needed.

' In order to prevent the development of a vacuum in thesystem when itis cooled down, with the undesirable results explained, we providea--vac'ui1m breaker 41 in the upper part of the drum, although it willbe ob vious that this vacuum breaker might be placed in substantiallyany portion of the system, which normally holds steam during operation.This vacuum breaker may be of the types well known in the industries. In

the present form we show a body portion with a valve seat 42 with whicha valve 43 is adapted to cooperate to close the valve. This valve iscarried on a stem 43 extending through the valve casing with suitablepacking (not shown). A spring 46 determines the relative pressures atwhich the valve operates. .Normally, the valve would operate fullautomatically, but the projecting portion of the valve stem affords ameans for manually operating the valve should occasion require.

Connected into the pipe 39, we show a somewhat schematic valve means forventing the high pressureline until a pre-determined pressure isdeveloped therein. This includes a pipe 47 connected into the pipe 39,which communicates with a valve casing 47. This valve casing contains avalve, including a seat 48 and a valve body 49, through the operation ofwhich flow of steam through the pipe 47 is controlled. For the operationof the valve 47 a diaphragm type of valve 51 is provided having adiaphragm 52, one side of which is under the same pressure as the pipe47 through a small pipe 53 communicating with the pipe 47 and one sideof the diaphragm. A spring 54 at the opposite side of the diaphragmopposes a pre-determined pressure against the steam pressure. Thediaphragm has connected thereto a valve stem 56, which extends throughthe two valve casings and carries the valve 49, which thereby is causedto open or close by the movement of the diaphragm 52. The spring 54 isset to exert any pre-determined pressure and will, therefore, hold thevalve in an open position until a sufiicient steam pressure is developedat the opposite side of the diaphragm to overcome the force of thespring and close the valve.

The steam discharged throu h the valve casing 47 is delivered to a pipe5 which pipe 57 may communicate with any portion of the system. One verysatisfactory arrangement is shown in Fig. l, in which the steam from thepipe 57 is discharged onto the engine 11, thereby warming this engine upduring the starting period of the steam generating system so that whenthe steam has reached the required pressure, the system as a whole is inthe most efficient condition for operation. This provision is foundto bevery desirable during the cold weather when the engines which areusually placed under the car are exposed to the outside temperature andmay be quite cold.

Since considerable electrical current is employed for the operation ofvarious controls and the like, (not shown) an auxiliary steam engine 58is usually provided for driving a generator 59, which supplies power tothe electrical portions of the system. This auxiliary engine may also befed with steam bled from the pipe 39 during the starting up period,apipe 61 being shown communicating with the pipe 57 for-the purpose.Suitable valve mechanism is provided for directing the steam from thepipe 57 to the point where it is to be used. It will be understood thatthis steam may be discharged into any part of the system or for thatmatter into the atmosphere. A pipe 62 is indicated in Fig. 1 for thispurpose.

From the foregoing description it is believed that the main operatingfeatures of the system will be understood. Taking a hot system with fullsteam pressure and allowing it to cool, the vacuum breaker allows airfrom the outside to enter the system to take the place of the steamnormally present in parts thereof. When the system is standing coldrelatively large amounts of air at close 'to atmospheric pressure arepresent. During the firing period some of this air undoubtedly is drivenby expansion directly out through the bleeder opening, but parts of thisair will be mixed with the steam as -it is generated and eventually willfind its way up to the condenser either through the exhaust pipe 63 fromthe auxiliary engine or through the exhaust pipe 64 from the mainengine. We provide means eifective to exhaust this air so that thesystem when brought completely up to operating pressure will consistsubstantially entirely of water and steam.

. The condenser discharges its condensate through a pipe 66 into a watersupply tank 13, this pipe 66 discharging below the surface of the waterfor several reasons readily understood, among the most important beingto build up just suflicient back pressure in the condenser to cause theproper distribution of exhaust steam therein. If uncondensed steam,which may be present, as well as air which was sucked into the system oncooling, is delivered under water to the tank 13 it readily escapes outthrough a vent opening 67 provided in the tank. It is readily seen thata very short time after the system starts to operate, even though thesteam pressure is still low, substantially all of the air will have beendriven off.

In connection with the relieving of a vacuum in the system to preventdisplacement of water, substantially the same result can take placebetween the condenser and water supply tank when the condenser coolsbelow the normal operating temperature thereof. For this reason we alsoprovide a vacuum breaking valve 67 at a suitable place in the condenser.Air admitted to the condenser through this valve is quickly exhaustedthrough the opening 67 when the condenser again starts functioning.Although as a general rule the condenser will be maintained at asufliciently high temperature during operating to prevent the creationof an undesirable vacuum therein, in very cold weather if the car standsfor some time, for example in a station for discharging and taking onpassengers and baggage, the condenser may be cooled to such an extent asto create a partial vacuum. The valve 68 is designed to relieve thisvacuum before it is sufficiently low to allow air above the water in thetank 13 to force the water back into the condenser. In extremely coldweather any large amount of water driven up into the condenser from thetank 13 might freeze in such a way as to cause a temporary stoppage ofthe system. The relief valve 68 functions also to relieve the vacuum inthe condenser when the system is shut down, occasioned by extinguishingthe main burner.

In Fig. 1 the ordinary steam line 39 communicating with the engine willnot pass steam to the engine during the firing period for severalobvious reasons. In the first place this steam line is controlled byvalves including throttle valves, which normally are closed and so cutoff the flow of steam to the engine. It will be understood that theshowing of Fig. 1 is to a large extent schematic and no throttle valveis shown. In addition, the steam admitted to the engine from thethrottle valve delivers steam through the valve system to the tops ofthe cylinder heads for driving the engine. It will readily be understoodthat although some heating effect would be obtained in this way, thereis nothing approaching the results obtained when the steam is passedthrough the sump of the engine, as the drawings illustrate.

From the description of the system, it is clear that we employ a newstarting method, practiced, it is true, preferably by a system of thecharacter shown, but adapted to be practiced in other ways. Since thesteps of the method are clearly understandable by a description of theapparatus, no detailed explanation of the method will be made.

That beneficial results are obtained by means of our system and thepractice of our method appears clear when the operation of the injectoron starting is considered. In the old system without the vacuum reliefmeans and bleeder means of our invention, the injector usually failed tooperate until approximately 400 lbs. of pressure had been developed inthe system, the system being designed to operate at about 650 lbs.pressure. It is clear that during this time such 'movement of fluid asmight have taken place within the coils was not of a character either toprotect the tubes or to obtain the best and quickest starting results,inother words, normal circulation had not been established.

We have found that with the method of our invention as practised withthe apparatus shown, the injector starts operating when not more thanlbs. of pressure has been developed in the system. This means that whenthe temperature of the coils is still early stages, is manifest.

relatively low normal circulation has already been established. Wefurther attain the objects of the invention by the selection of certainspecific types of materials from. which to construct the coils. Thecoils immediately adjacent to the burner are formed of material havingrelatively low thermal conductivity, while those farther away from theburner have relatively high thermal conductivity. In actual practice thematerial used in the evaporating and super-heating coils is a high gradealloy steel having relatively high heat resistance, while the pre-heatercoils are constructed of an ordinary good grade of steel tubing, havingsubstantially the same heat conductivity in actual practice as ordinarypure iron.

The operation and function of the steel tubing of our selection as isfollows. When the burner is first fired with the coils cold, ordinarysteel tubing would absorb a very large proportion of the heat, leavingonly a relatively small residual amount of heat for the pro-heatercoils. This would be true, particularly when the system was very cold,on account of the relatively great temperature drop between the burnerand tubes. When a metal with relatively more heat resistance is usedadjacent the burner, less heat is absorbed, and more heat reaches thefar ther removed pro-heater coils. Since the circulatory movement isfrom the coils farthest away from the burner, toward those closest tothe burner, the effect on the circulation of different types of metals,at least in the Relatively low heat conductivity in the coils adjacentthe burner tends to aid in establishing normal circulation in the earlystages from a fully cold start; while evaporating coils of high thermalconductivity tend to cause reverse circulation, or arrested circulationat this time.

Not only does this selection of materials aid in the establishment ofnormal operation early during the firing period, but the tubes 1n theimmediate fire zone are further protected by the high quality andgreater strength of the alloy steel. In case the tubes are overheated,due to shortage of water in the tubes, possibility of damage islessened.

We wish to call attention to the position of the drum 34, the bottom ofthe drum being substantially even with the top of the coils. Thispermits the flow of water by gravity to the coils when the system iscooled, thereby insuring that the tubes will be entirely filled withwater when the system is started. It Will be understood thatsubstantially the same result can be obtained if the drum isapproximately even with the tubes, but this would be only if more than ausuall lar e supply of water were available in tie tu e and drum portionof the system. For ordinary peration the elevated position of the drumis to be preferred.

What I claim as new and desire to protect by Letters Patent of theUnited States is 1. In a steam boiler system, a burner, a plurality ofcirculating coils disposed about the burner, a steam and Waterseparating drum, connections between the coils and said drum, and vacuumbreaking means at the top of the drum to prevent water from being suckedout of the coils and into the drum when the system is cooled.

2. In a steam boiler system, a burner, a plurality of circulating tubesdisposed about the burner, a steam and water separating drum,connections between the tubes and drum, a steam line extending from thetop of the drum for delivering'steam to a source of power, and means forventing said steam line during the firing up period of the boiler, saidventing means including a pressure responsive valve adapted to close inresponse to increased pressure on the inlet side thereof.

3. In a steam boiler system, a burner, a plurality of circulating tubesdisposed about the burner, a steam and water separating drum,connections between the tubes and drum, a steam line extending from thetop of the drum for delivering steam to a source of power, means forventing said steam line during the firing up period of the boiler, andvacuum breaking means at the drum to prevent water from being sucked outof the tubes and into the drum when the system is cooled.

4. In a steam boiler system, a burner, circulating evaporating coils andwater preheating coils disposed about the burner, a steam and waterseparating drum adapted to contain a body of water and a body ofsuperimposed steam while the system is operating,

connections between said coils and the water containing portion of thedrum, and vacuum breaking means in the steam portion of the drum toprevent drawing water from the coils into the drum.

5. In a steam boiler system, a burner, water pre-heating, evaporatingand steam super heating coils disposed about the burner, a steam andwater separating drum having water and steam connect-ions to said coils,and means for venting the superheater coils during the firing period ofthe boiler, whereby normal water and steam circulation is promoted, saidventing means including a pressure responsive valve adapted to close inresponse to increased pressure on the inlet side thereof.

6. In a steam boiler system, a burner, water pro-heating, evaporatingand steam superheating coils disposed about the burner, a steam andwater separating drum having water and steam connections to said coils,means for venting the super-heater coils during the firing period of theboiler whereby normal water and steam circulation is promoted, andvacuum breaking means in the drum to prevent drawing water from thecoils into the drum when the system is cooled, whereby water isavailable in the coils at all times dur ing the firing period.

7. In a steam boiler system, a burner, water pre-heating, evaporating,and steam super-heating coils disposed about the burner, a steam andwater separating drum having water and steam connections, said steamsuper-heating coils extending from the top of the drum and adapted todeliver steam to a source of power, means for initially bleeding thesuper-heating coils when the burner is first ignlted, and means forrendering the bleeder means inoperative when a predetermined steampressure is attained in the superheating coils.

8. In a steam boiler system, a burner, water pre-heating, evaporating,and steam superheating coils disposed about the burner, a steam andwater separating drum having water and steam connections, said steamsuper-heating coils extending from the top of the drum and adapted todeliver steam to a source of power, means for initially bleeding thesuper-heating coils when the burner is first ignited, means forrendering the bleeder means inoperative when a predetermined steampressure is attained in the system, and means'for relieving the vacuumin the system when the burner is extinguished and the system allowed tocool.

9. In a steam boiler system, a burner, water pre-heating, evaporatingand steam super-heating coils, a steam and water separating drum havingconnections to said coils, means for admitting air to the drum and coilsto relieve vacuum created by condensation of steam when the system iscooled, and means for removing said air from the system when such systemis again operated to produce steam.

10. The method of starting a steam system of the type comprising aburner, circulating coils including steam super-heating coils, and asteam and water separating drum for delivering saturated steam to saidsuper-heating coils, which comprises firing the burner, and bleeding thesuper-heating coils to initiate substantially immediate normalcirculation, and closing said bleeding means when a pre-determined steampressure is attained in the super-heating coils.

11. In a steam boiler system, a burner, a plurality of circulating coilsdisposed about the burner, a steam and water separating drum positionedabove the coils, connections between the coils and drum and vacuumbreaking means to prevent the water from being sucked up into the drumand out of the coils when the system-is cooled, the position of the drumabove the coils permitting r the water to flow by gravity from the druminto the coils when the vacuum in the system is relieved.

In witness whereof, we hereunto subscribe our names this 26th day ofJanuary, 1931.

v WILLIAM M. RYAN. 'CLYDE B. FAVERTY.

